1. Field of the Invention
The present invention relates to a broadband wireless communication system that supports a femto base station. More particularly, the present invention relates to a system structure and a method for providing a Local BreakOut (LBO) service when a terminal uses a femto base station.
2. Description of the Related Art
A femto cell denotes a cell in a cellular system that covers a very small service area such as a household or an office, and a base station that services the femto cell is called a femto base station. The femto base station is an ultra small base station that accesses a mobile communication core network via a broadband network installed in an indoor space such as a household or an office, and operates with low power. The femto base station provides various advantages such as extending the cellular coverage indoors, improving communication quality, and efficiently providing various wired/wireless fusion services. In addition, the femto base station provides many advantages for a subscriber and related service providers. For user convenience, handover for voice/data service between macro or femto cells should be guaranteed, and control of user access by an access control should be possible. In addition, differentiated charging/accounting alternatives according to a femto cell-based service scenario and reliable data should be provided.
A 3rd Generation Partnership Project (3GPP) group defines a Wideband Code Division Multiple Access (WCDMA)-based Home Node B (HNB) and a Long Term Evolution (LTE)-based Home evolved Node B (Home eNB) as a femto base station. In addition, the Institute of Electrical and Electronics Engineers (IEEE) 802.16 standard calls a femto base station a WiMAX Access Point, and defines a network for a femto cell.
Currently, traffic of a terminal inside a femto cell is transmitted via a transmission path of a mobile communication service provider network. Therefore, data of all terminals in a femto cell should be transmitted via a transmission path of the mobile communication service provider network. That is, all Internet traffic occurring in hundreds of thousands to millions of femto base stations is transferred to an Internet network via a femto gateway of the mobile communication service provider. Based on this substantial amount of traffic, a femto service provider needs to operate a large-capacity femto gateway and a large-capacity core network that can process all traffic occurring in femto base stations. This acts as a factor that increases Capital expenditures (Capex) and Operational expenditures (Opex) of a service provider. In addition, in the case in which an existing macro network service provider intends to provide a femto service using an Access Service Network-GateWay (ASN-GW) of a macro system, a problem of having to increase the capacity of a macro core network occurs.
Therefore, a method and an apparatus for preventing a load from being concentrated on a femto gateway in a wireless communication system that supports a femto base station are required.